A primary fluid (which may be hot or cold depending on circumstances) passes through the tubes in a heat exchanger bundle, and serves to heat or to cool a secondary fluid, such as air, which crosses through the bundle.
Sometimes the heat exchanger is mounted in a housing which includes a conduit for circulating and guiding the secondary or external fluid. Since the heat exchanger bundle is generally substantially in the shape of a parallelipiped, the secondary fluid crosses through the bundle by entering one of the large faces of the parallelipiped and by leaving through the opposite large face, thereby passing over the fins or other heat exchange surfaces which are provided on the tubes and which extend parallel to the direction of flow of the secondary fluid.
In order for the heat exchanger to have acceptable efficiency, it is important to prevent the secondary fluid from flowing round the bundle rather than through it. For this purpose, proposals have already been made to close the lateral faces of the bundle, i.e. the faces extending perpendicularly to the large faces through which the secondary fluid flows, by various suitable means, such as by having ribs on the sides of the housing for co-operating with said side faces of the bundle, or by pressing or gluing sealing means to said side faces, etc.
Some of the known means are not very effective, while others are expensive, or else, once fixed on the side faces of the bundle, they hinder its insertion and assembly in said housing.
Preferred embodiments of the present invention provide a simple, effective and cheap solution to the above problem of sealing the sides of a heat exchanger bundle.